The cast metal from the twin-belt continuous casting machine is synchronized with, and directly fed into, a hot rolling mill. Usually the ladle sits in a slot on a rotating turret at the casting machine. When casting wide strip, the tendency of localized thermal distortion can be resisted by the use of high-strength, magnetic belt back-up support rolls within continuoys mold region.
Aluminium and copper can be cast horizontally and can be more easily cast into near net shapeespecially strip, due to their lower melting temperatures. The PLC can also set the mould oscillation rate and the rate of mould powder feed, as well as the flow of water in the cooling sprays within the strand. Molten Metal Level Control: The twin-belt casting machine differs from other moving mold casting machines in that all four mold surfaces are independent. Molten metal is introduced into the twin-belt continuous casting machine from a tundish through a nozzle placed between the casting belts.
Similarly, the incoming liquid metal may be too hot and the final solidification may occur further down the strand at a later point than expected; if this point is below the straightening rolls, the shell may break from stresses applied during straightening. From the ladle, the hot metal is transferred via a refractory shroud pipe to a holding bath called a tundish.
Direct strip casting is a continuous casting process for producing metallic sheet directly from the molten state that minimizes the need for substantial secondary processing.
Horizontal continuous casting of steel
Each time the caster stops and restarts, a new tundish is required, as any uncast metal in the tundish cannot be drained and instead freezes into a ‘skull’. In this case, the upper belt pulley is offset downstream from the ckntinuous pulley.
A storage ramp is provided to support the flexible end in the stored position. For example, when casting copper anode plate the cast slab is not rolled but rather sheared directly into distinct anode plates. The starter bar is constructed in discrete blocks secured to one side of a planar spine provided in segments and arranged end to end. Special dam blocks which contain anode lug molds and a traveling hydraulic shear are added to the twin-belt casting stee to continuously cast net shape copper anodes.
To increase the rate of solidification, the strand is sprayed with large amounts of water as it passes through the spray-chamber; this is the secondary cooling process. The cooling belts are typically made of low carbon steel and are held under tension within the casting machine to ensure flatness and accuracy.
High-speed continuous casting of peritectic carbon steels – ScienceDirect
The primary advantage of this process is uniformity of the as-cast anode in terms of size and surface quality. In addition to preventing thermal distortion, the high preheat xasting serves to eliminate any moisture present on the belt surface. The metal is cooled by direct contact with the belts which are in turn cooled by high pressure recirculating water. Articles lacking in-text citations from July All articles lacking in-text citations.
This allows cotninuous mold surfaces to be tapered to remain in contact with the cast product as it shrinks. The Minerals, Metals, and Materials Society. Chains of rectangular steel or copper blocks moving with the belts and spaced according to the desired cast width form the sides of the mold.
When casting other metals, such as copper, dowbload and lead, an open pool feeding system is often used. Metal is drained from the tundish through another shroud into the top of an open-base copper mold.
Molten metal is tapped into the continuosu from furnaces. These forces can be controlled by preheating the belts before mold entry, or by magnetically stabilizing them once they have entered the mold. Production rates and speeds: The tundish allows a reservoir of metal to feed the casting machine while ladles are switched, thus acting as a buffer of hot metal, as well as smoothing out flow, regulating metal feed to the molds and cleaning the metal see below. As the term boil suggests, this reaction is extremely fast and violent, generating large amounts of hot gas, and is especially dangerous if it occurs in the confined spaces of a casting machine.
Materials Science and Downloaf Here, the metal is introduced under slight pressure into the closed mold cavity. Each side of the mold is formed by an endless chain of dam blocks,which are held against the cast strip by adjustable spring-loaded guides.
In this type of machine, either strand or mold oscillation is used to prevent sticking in the mold.